How do I display the new comment in the comments section when added and still keep the submission ajax code?

[Immortal2004]

My code is below:

 $commentsQuery = "SELECT username, created_at, content FROM comments WHERE post_id ={$row['id']}  ORDER BY created_at DESC";
$commentsResult = mysqli_query($con, $commentsQuery);
$commentsCount = $commentsResult->num_rows;
if ($commentsCount > 0) {
  echo "<details>
    <summary><p style='font-size:12px; cursor:pointer; text-align:left; margin-left:10px; margin-top:17px; font-weight:600; margin-bottom:0px; color:white'><img src='comment.svg' style='width:16px; filter:invert(1); margin-bottom:-3px'> Comments ({$commentsCount})</p></summary>
    <br>
<div class='comments-section' style='max-height:270px; overflow-y:auto; overflow-x:hidden' id='comments_{$row['id']}'><h2 class='sr-only'><img src='comment.svg' style='filter:invert(1); width:16px; margin-bottom:-3px'> Comments</h2>";
  while($comment = mysqli_fetch_assoc($commentsResult)) {
    echo "<div role='article' class='comment-card' style='margin:10px; border-radius:7px'>
      <p style='font-weight:600; margin-bottom:-8.5px; margin-left:10px; margin-top:3px'><a href='profile?username=".$comment['username']."' title='Click to view ".$comment['username']."' style='font-weight:600; font-size:12px'>".$comment['username']."</a><span style='font-weight:700; float:right; background-image:linear-gradient(127deg, #00beff, #00aeff, #0083ff); margin-top:-4px; color:white; padding:2px 7px; border-radius:50px; margin-right:4px; font-size:12px'>{$comment['created_at']}</span></p>
      <p class='comment-content' style='background-color:white; border-radius:7px; margin-left:10px; margin-right:10px; font-weight:400; font-size:12px; padding:6px 10px; border:none'>{$comment['content']}</p>
<script>
function addComment(postId) {
    $.ajax({
        url: 'add_comment.php',
        type: 'POST',
        data: {
            title: $('input[name="title"]').val(),
            postId: postId,
            username: $('#username').val(),
            comment: $('#comment-' + postId).val()
        },
        success: function(data) {
            console.log("Got " + data.status);
        },
        error: function() {
            console.log('error');
        }
    });
    return false;
}
</script>